I understand that but when a pigtail is 4-6 inches with 4-12 wires, it's not always possible.
Environmental slices are superior to soldering for repairs
Only if you're not any good at soldering. Mechanical/tube splicing offers no advantage over a good solder joint with a sealing heatshrink tube over it except speed, and repeatability if you aren't good at soldering (but depends on quality splice tool still) and often has disadvantages such as size, weight, cost.
There are those who want to claim problems like wire fatigue, oblivious to the fact that if soldered properly, there is less fatigue than mechanical splicing.
I'm not arguing do it one way or the other, rather either will work so do it the way you're best at.